Loading map...

1966 Map of Cucamonga Peak

Name: 1966 Topographic Map of Cucamonga Peak
Creator: U.S. Geological Survey
Published: 1975
License: https://creativecommons.org/publicdomain/mark/1.0/

USGS Topo · Published 1975

About this map

Alta Loma and the surrounding foothill communities of Cucamonga and Etiwanda sit at the southern edge of the San Gabriel and San Bernardino Mountains during a period of significant suburban expansion. The 1973 revisions, marked in purple, illustrate the rapid transformation of agricultural land and open washes into residential grids, particularly around Chaffey Union Jr College and along corridors like Banyan St and Lemon Ave. This growth pushes directly against the Cucamonga Wilderness and the Angeles National Forest, where steep terrain and deep canyons like Deer Canyon and Day Canyon remain largely untouched.

Transportation and water management infrastructure define the lower landscape, with the Atchison Topeka and Santa Fe and Southern Pacific railroads crossing the southern flats. A network of flood control features, including the Flood Control Basin and debris dams in Demens Canyon, highlights the ongoing challenge of managing runoff from the high peaks of Cucamonga Peak and Ontario Pk into the developing valley floor.